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View Full Version : What is the best way to remove carbon?



ichthos
08-27-2009, 12:21 AM
I am trying to remove the carbon build up from the top of my pistons and the inside of my cylinder head. What is the best way to remove these deposits?

Kevin

pjsmetana
08-27-2009, 05:56 AM
Use a wooden or plastic scraper and some solvent. <span style="font-weight: bold"><span style="text-decoration: underline">DONT FORGET YOUR PPE!!!</span></span> After cleaning the best you can with that, you can move on to a BRASS wire brush, used gently, and some steel wool. Take your time and get her as clean as you can without marring up any metal surfaces. There are some other, faster, easier techniques out there, but most of them require many specifics and can result in needing to start over with a new head.

As far as 'what solvent', thats a good question, as I don't know for sure whats for sale and legal any more. But I do know that regular gasoline has worked well, as have some older waterbased solutions. Best thing for this is probably a stroll through the autoparts store and see what they are selling. Who knows, maybe the carbon/grease eating microbes are legal now...

DrEntropy
08-27-2009, 06:43 AM
That's it. Additionally ya do NOT want to get any of it down between the bore and pistons. It'll scar the walls instantly. If the engine were in bits I'd suggest "EasyOff" oven cleaner, the goop not the spray. Rather than take the chance of scoring the bores you could leave it, reassemble and use a spray bottle with water down the carb throats at 3K RPM. That burns off most of the kak in there without the chance the stuff will ruin the bores.

tomshobby
08-27-2009, 08:49 AM
I did mine the easy way. Left last Thursday and returned Sunday afternoon. Traveled 1995 miles through six states. Wisconsin, Illinois, Missouri, Kansas, Oklahoma, and Arkansas. Clean as a whistle when I got back.

poolboy
08-27-2009, 08:57 AM
Kevin, if the pistons you want to clean are the ones in the engine in your driver, I wouldn't go overboard with the cleaning. I'd loosen some of it and vacuum the debris. Even Bentley says it's OK to leave the carbon around the perimeter.
If it's the spare engine's pistons you want to clean, I say, take them out and examine them or have a machinist examine them before going thru the trouble of cleaning them.
My machinist spotted some things on my pistons and convinced me to replace them with new ones.
https://i233.photobucket.com/albums/ee300/poolboy_album/100_0979.jpg
Bottom line, I guess would be, if you are just going to swap heads for now, keep everyhing else to a minimum.
If you are going to do a complete rebuild, then that's another story.

Mickey Richaud
08-27-2009, 09:00 AM
:iagree:

Now's not the time to tempt fate!

Keep it simple.

pjsmetana
08-27-2009, 09:25 AM
...ya do NOT want to get any of it down between the bore and pistons. It'll scar the walls instantly...

Great point Doc! If you do happen to get some down there, some compressed air usually handles it. Personally I wouldn't worry about whats on the pistons. I would clean the head fairly well, then do the water misting trick after reassembly.


... reassemble and use a spray bottle with water down the carb throats at 3K RPM. That burns off most of the kak in there without the chance the stuff will ruin the bores.

Yeah, that trick. When Doc suggested this to me about 3 months ago I thought it was ludicrous... but I also thought "what do I have to lose?" so I tried it. And believe it or not, it not only cleaned off 90% of the junk on the head and pistons, it removed the rust that was on cyl#3's rings and unstuck them. Saved me a rebuild, at least for a while. Just from that I no longer leak or burn (much) oil. It starts faster, has more power, and I even get better gas mileage (not that mileage matters much in a weekend warrior sports car). Doc is the one who gave me all the specifics and so on about this trick, so I don't mind passing it on. The more who know, the better... especially in these days of Low-Lead, Ethanol Enriched, Goopity-Goop we are all forced to run.

Andrew Mace
08-27-2009, 09:57 AM
Kevin, if the pistons you want to clean are the ones in the engine in your driver, I wouldn't go overboard with the cleaning. I'd loosen some of it and vacuum the debris. Even Bentley says it's OK to leave the carbon around the perimeter.Back in the days when "decoking" or "decarbonising" was pretty much a routine maintenance item, many manuals suggested using an old piston ring as a "guide" to your piston-top scraping. That said, nowadays I think Tom's method is as good as any. Along those lines (and I'll try to be careful in wording this) there was the old proverbial "Italian car tuneup" consisting of running the "snot" out of the engine on the highway (kinda like what Tom did, although usually not 2000 miles' worth)! :driving:

tomshobby
08-27-2009, 12:33 PM
And Andy, it was so much fun especially in the Ozarks.

tdskip
08-27-2009, 08:59 PM
How much water to you mist into the engine while it is running to do this?

tomshobby
08-27-2009, 09:12 PM
How much water to you mist into the engine while it is running to do this?


Only what was in some low clouds we ran through in the Ozarks between Sullivan and St Louis on the way home Sunday.

tdskip
08-27-2009, 09:30 PM
How much water to you mist into the engine while it is running to do this?


Only what was in some low clouds we ran through in the Ozarks between Sullivan and St Louis on the way home Sunday.

So I have to wait until I'm east of the Mississippi to do this, or maybe go visit Don in Seattle. Oh wait, it never rains in Seattle anymore. &lt;grin&gt;

Seriously though (you knew that was coming), how much water?

DNK
08-27-2009, 11:19 PM
How much water to you mist into the engine while it is running to do this?


Only what was in some low clouds we ran through in the Ozarks between Sullivan and St Louis on the way home Sunday.

So I have to wait until I'm east of the Mississippi to do this, or maybe go visit Don in Seattle. Oh wait, it never rains in Seattle anymore. &lt;grin&gt;

Seriously though (you knew that was coming), how much water?



Intentional foul
Forum cross over!

ichthos
08-28-2009, 12:02 AM
I ran a quart of water through mine. I'll let you know how well it worked in about a week when I pull the head.

Kevin

DrEntropy
08-28-2009, 05:50 AM
A QUART?!?! The spray bottle on wide pattern and a few squirts down each throat with the throttle holding three grand should do... I'd say it would be measured in ounces. It'll stumble and object to the mix but if kept running it should be sufficient to burn off the loose buildup.

If the thing is headed for a tear-down I don't think I'd worry over it! Or give it Andy's treatment. Last time I posted reference about an Italian Tuneup I got piled on for bein' "un-PC". ~WE~ didn't invent the term... it came from racing.

Additionally: ~I'm~ of ITALIAN extraction. I find th' phrase flattering. :wink:

pjsmetana
08-28-2009, 06:00 AM
How much water to you mist into the engine while it is running to do this?


I did 2 cups of water per carb barrel @ 3000 RPM, then drove it like an Idiot for a few miles... maybe I did 50 miles, but I like t' drive.

Don Elliott
08-28-2009, 06:17 AM
When I restored my 1958 TR3A from 1987 to 1990, I re-built the engine with new pistons, rings and liners. In 2007, after driving 94,00 miles on the "new" engine, I decided to do another re-build. All I had to do was clean it up and change the rings. Naturally at the same time, I installed new gaskets, new bearing inserts all around, etc. The 4-ring Hapolite pistons from 1990 were very clean. During those 17 summers of driving, I had used un-leaded and there was nothing to "de-coke". I'm certain that modern gasoline leaves your engine cleaner than leaded did during the first life of my engine from 1958 to 1990.

Tabcon
08-28-2009, 10:29 AM
Are you going to remove the cylinder head to do this, or do you just want to squirt some type of goop into your intake?

If it's bad enough, I would remove the head and have the chambers soda blasted.
You could probably do the same to the tops of the pistons as well while still in place since baking soda is not abrasive enough to harm the cylinder walls and should dissolve rather easily. You would have to be careful and cover up and/or mask off anything you don't want baking soda in or on.

UmmYeahOk
08-31-2009, 11:06 AM
Whenever I want to remove carbon from my engine, I just let my husband drive for a while.

Seriously though, does any one know if seafoam will hurt these little old engines?

RobT
08-31-2009, 08:07 PM
I agree with Andy - always been a big fan of the good ol' Italian Tune-up. Sometimes you just gotta blast the gunk out. Kind a fun too. Just think of the red line as a target rather than a limitation.

Rob.

tdskip
08-31-2009, 09:35 PM
I tried using a spray bottle on a heavy mist today and.... nothing. Not sure if I didn't use enough water, or if there just might not be a build up of carbon for the water to dislodge.

pjsmetana
09-01-2009, 08:17 AM
I tried using a spray bottle on a heavy mist today and.... nothing. Not sure if I didn't use enough water, or if there just might not be a build up of carbon for the water to dislodge.


Its not exactly like your gonna see chunks of carbon flying out of the tail pipe. When I did this it didn't seem to make much of a difference till I went out for a drive. How much water did you use?

tdskip
09-01-2009, 08:40 AM
Not that much Pete. A couple squirts on a misting setting, not much at all. Didn't even result in the car stumbling.

DrEntropy
09-01-2009, 09:22 AM
You'll want to see white "smoke" from the exhaust, engine protesting... If ya are gonna get enough in there to do the job, anyway.